SYDNEY (Reuters) - Global miner Rio Tinto <RIO.AX><RIO.L> boosted its forecast copper output for 2013 after a better-than-expected recovery from the U.S. Kennecott mine following a landslide, and posted record iron ore and coal output in the third quarter.

Copper output was also buoyed by a ramp up in production at the Oyu Tolgoi mine in Mongolia, while Rio Tinto said it was on track to beat its target of cutting $750 million (469 million pounds) in exploration spending this year.

Shares in Rio extended gains after the report, up 2.5 percent to a near three-week high and outperforming the broader index <.AXJO>.

"Copper's come in well ahead of most people's expectations, and there's a pretty chunky production guidance upgrade there," said Chris Drew, an analyst at RBC Capital Markets.

In Australia, productivity improvements led to record quarterly thermal coal and iron ore production and shipments in the third quarter, the company said.

Iron ore shipments, which rose 4 percent from a year ago and 11 percent from the previous quarter were helped by expansion work on ports and rail lines in Western Australia, Rio Tinto said in its third-quarter production report.

A planned expansion in annualised output to 290 million tonnes would come in by the end of the first half of 2014, ahead of time and under budget, it said.

Guidance for iron ore output in 2013 was unchanged at 265 million tonnes.

"We maintained good progress against our strategic priorities to improve the performance of our businesses, strengthen the balance sheet and deliver our approved growth projects," Chief Executive Sam Walsh said in the report.

At Kennecott, Rio Tinto says it expects the mine to yield 185,000 tonnes of copper in 2013, up from only 150,000 tonnes forecast in July, citing greater progress on building a new road to help in waste removal and remediation work.

An avalanche of dirt buried the northeast section of the open-pit mine on April 10.

Rio Tinto initially said it expected production at Kennecott to drop by at least 50 percent in 2013.